The display needs a bit of special attention to work properly in the Raspberry Gear. The display is designed to accept from 6V-12V, which is just a mite too high for our 5V system. Testing it with 5V will work somewhat, but it'll be choppy and pretty much unusable. So what to do? Well, the screen's controller board actually uses a combination of 5V and 3.3V, but the input power (6V-12V) has to pass through a regulator. And, no matter how LDO this little regulator might be, it just isn't quite enough.
The display controller board needs to be modified to accept direct 5V, by removing that regulator! Pay careful attention to the orientation of the board in the photos, to ensure you solder onto the right pins!!
(If you absolutely do not want to try and desolder the chip, you should be able to clip all of the leads carefully using your flush cutters! However, do not apply excessive upward force doing this, or you can damage the pads!!)
The part is an SOIC-8 part, which means four leads on the top and four on the bottom. Our target chip is highlighted in red below. It's gotta go!
The trick to desoldering these types of parts is to apply a glob of solder to your iron, flow the entire side of pins, and then (while it's still hot/liquid) gently lift that side with your tweezers.
Once the chip is gone, we're going to run two small wires to the main connector, so you can continue using it for power input! The pads are marked below.
(And, so you can see what this looks like without the colored pads in the way...)
The 5V wire should be run to the 12V pad on the display's connector (pin 1), and the GND wire should be run to the GND pad on the display's connector (pin 2).
Now, you're ready to rock that 5V supply! It helps to apply a couple small drops of hotglue to hold down the yellow wires. Don't apply glue directly to the solder pads, as you risk damaging the pads if you have to remove the glue. Try and aim for a neutral empty area.
Finally, you can depin the white and yellow wires on the display connector, and remove them. Then, snip the Composite connector from the blue and green wires. Solder the wires onto a 4 pin male header in the following order:
- Blue (Composite Signal)
- Green (GND)
- Black (GND)
- Red (5V)